Official Luthiers Forum!

I'm getting ready to build some outside molds for a couple of body styles I'd like to make and was looking to get some opinions on whether an adjustable multi-style type mold worked as well as a solid one-style type.

My problem is limited storage space and that's why I'm looking at the Multi-style. I would be building this mould myself, althoughj I have seen a few types on the 'net.

Thanks,

Cal

_________________
Remember, there are no stupid questions, only stupid answers!

There are times and procedures when you need the sides to be held in place securely, as when you are sanding the rims in a sanding dish, for instance. I am not convinced that the multi-style molds (which I have no experience with) are as secure as the solid type. So, a caution from me about multi-style (at least the ones I have seen).

Both types have advantages and disadvantages but for the most part in steel string construction, solid forms have greater advantage as you can't miss set the position of the sides or center line as is possible with the adjustable dowel type mold. Plus while possible to make the adjustable type work for more than one guitar IMO they don't do a good job of it when trying to make it work for more than one size body it is difficult to get the center axis of the waist dowel to be in the right position for all body shapes. Also no matter how tight you tighten the adjustable dowels they have an inherent amount of deflection.

Solid for me. Block the sides in place once bent, leave them blocked in place until back and top are glued on, while still being able to access both sides.

Thanks Steve, Micheal and Mattia,

I kind of had a suspicion that adjustable molds would have drawbacks to solid, but I just had to see if anyone felt otherwise.

The point about the waist area not lining up and side deflection makes a lot of sense, Michael. I had a feeling that there may be problems like that.

Cal

_________________
Remember, there are no stupid questions, only stupid answers!

I agree with the above posts. One size fits all doesn't seem to work well for me in this situation.

Mine are not quite solid. They're two layers of 3/4" ply with 3/4" spacers sandwiched between, for a depth of 2-1/4". Seem to work for me. Others like 'em solid and deeper.

_________________
now known around here as Pat Foster
_________________
http://www.patfosterguitars.com

Edit:

Don't know how I posted this twice, but I did!

_________________
now known around here as Pat Foster
_________________
http://www.patfosterguitars.com

I have an "universal" dowel type mold somewhere and I made some guitars with it, but I never really liked it. I guess it is OK if you do a lot of quick, experimental body shapes, but its big drawbacks (for me) are that it is heavy and bulky and you can only access the inside of the rims from one side. Solid forms need not take much time to make, and if you are careful when you cut it on the band saw you can use the waste material in your Fox bender.

<edit> BTW, I never had any problems with the dowels flexing or anything like that, it kept the rim's shape just fine, but one more problem is that it can't be used as easily with the radius dishes.

_________________
Rian Gitar og Mandolin

Well here is a dissenting opinion.
I was using rigid molds until I took the Fox course in 2003 and was shown the correct way to build and use the outside molds. I built two and that's all I use now. I actually like them better than the rigid mold. I've used them on 21 guitars and have done some minor mods and also made attachments for various operations. You set up a good centerline and use the half template to set the posts on one side, then flip it over to set the other side. It's extremely accurate.
I made some shorter end blocks for radius sanding. With proper internal support spreaders it's been very stable during radius sanding.
You do have to figure out what body shapes you will be using and take that into consideration when cutting the slots.
Overall I've been very happy with the adjustable molds and my rigid molds are getting moldy.
Bottom line is both types work great, there's always more than one way to skin a cat.
Terry


Setup for clamping end blocks


Setup for radius sanding with a central pivot and shorter end blocks


Radius sanding


Gluing the back

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

How do you radius the front of the guitar?

Mike,
Since my sides are profiled before bending I usually glue the back kerfing (reverse type) before sanding and then radius sand the back. I then take the rimset out of the mold and flip it over, put it back in, and level it with a block under the headblock and wedges under the sides so that it is perfectly square to the floor of the mold. Replace the spreaders, and glue the top kerfed lining and radius sand. The wedges provide good stability during sanding.
I've also got a jig for this mold to angle the upper bout so it will match the neck angle. It's basically a bar that straddles the rim at the location of the bridge and is about 1/16" thicker than the bridge. I can use this as a pivot point and sand the upper bout with a flat sanding board with a 1/4" piece of plexiglass attached to represent the fretboard. This has proved quite accurate.
I know there are are many other ways to do these operations with rigid molds that work just as well but this is what I've evolved into and I'm really happy with it.
Terry
http://www.kennedyguitars.com


Setup with wedges ( Top rim has already been sanded in this picture and the back is already on)


Setup for upper bout angle sanding


Upper bout sandingboard


Gluing the top

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.